Lymphoid and myeloid lineage commitment in multipotent hematopoietic progenitors

Abstract

Hematopoietic stem cells (HSCs) continuously replenish all classes of blood cells through a series of lineage restriction steps that results in the progressive loss of differentiation potential to other cell lineages. This review focuses on the recent advances in understanding one of the earliest differentiation steps in HSC maturation, which involves the diversification of the lymphoid and myeloid cell lineages, the two major branches of hematopoietic cells. We discuss progress in the identification and characterization of progenitor populations downstream of HSCs, which has been a key to understanding the sequential biological events that take place along the course of differentiation into a certain hematopoietic cell type. We also discuss the importance of bone marrow microenvironment in lymphoid and myeloid lineage choice.

Fig. 1. Hypothetical structure of bone marrow in femurs

This figure is based on the gross structure of bone marrow described in Nilsson et al. (67) and experimental results shown in Lai et al. (31). PTX-sensitive GPCR-dependent movement of MPPs from the outer to inner region is necessary for proper lymphocyte development.